Proposal for Plot Based Plant Phenology Sampling in Puale Bay, Alaska (Adapted from Long Term Ecological Monitoring Program, Vegetation Sampling Protocols 2006)
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Plant Phenology Puale Bay 2010 Proposal for Plot Based Plant Phenology Sampling in Puale Bay, Alaska (Adapted from Long Term Ecological Monitoring Program, Vegetation Sampling Protocols 2006) Stacey E. Pecen U.S. Fish and Wildlife Service, Alaska Peninsula/Becharof NWR, P.O. Box 277, King Salmon, AK 99613 BACKGROUND AND OBJECTIVES Phenology, the timing of major biological events during a plant or animal’s life, can be monitored to detect changes in climate. Major events are called phenophases: leaf emergence, flowering, fruit ripening, and senescing. According to Menzel and Estrella (2001), plant phenology studies have shown that the average growing season is increasing by 0.2 days/year. It is especially important to monitor changes in higher latitudes, such as Alaska, where global warming is expected to occur earlier and at a greater magnitude (Henry and Molau 1997). The Northern Hemisphere (above 40o N) has experienced an increase in temperature of at least 0.5oC/decade from 1966-1995 (Serreze et al. 2000, Euskirchen et al. 2009). Monitoring species abundance and diversity is also vital. Environmental conditions dictate the composition of plant communities. Changes can occur over time, disrupting the balance of these interactions. In a nine year study at Toolik Lake, AK, Chapin et al. (1995) found that species richness declined 30-50% when the mean temperature was increased by 3.5˚C. Forbs and grasses decreased in abundance while woody species, such as Betula spp., increased. Changes in species abundance in regions of the arctic, as a result of warming, were also noted by Euskirchen et al. (2009). An increase in deciduous shrubs was observed, while moss and lichen declined. As the temperature increases, species may move to higher elevations in order to maintain habitats within their temperature tolerances, thus changing species density in affected areas (Root et al. 2003). Currently, there is not a long-term vegetation monitoring program in Alaska Peninsula/Becharof National Wildlife Refuge (AKPB NWR). A relevant plant phenology goal in the CCP includes Goal (31): Work with partners to contribute to understanding of climatic changes and their effects on refuge resources. Plant abundance and composition can be monitored with Goal 2 (21): Assist the Service’s Alaska regional botanist in completing the 1 Plant Phenology Puale Bay 2010 vegetation community classification for the Refuges. Implementation of a plot based method for monitoring plant phenology, composition, and abundance would help to accomplish these goals. PLANT PHENOLOGY Site Selection During the 2010 Puale Bay field season, observers surveyed six habitat types looking for target plant species. These habitat types included wet meadow, intermittently flooded alluvial deposits (creek bed), camp, hillside, cliffs, and a high disturbance area (runway). Each of these areas was surveyed for maximum diversity and high densities of plants found on the phenology monitoring species list (Appendix A). At favorable locations according to these criteria, GPS coordinates were taken (Table 1). Plant species observed in each proposed phenology monitoring plot can be found in Appendix B. The concept of plot based sampling was not formulated until mid-season, thus species displaying early phenophases may not be included in the plot species lists. It was found that this design was sufficient to capture most target species between the six plots. GIS locations, representing the northwest corners of potential plots, are presented in Figure 1. Plots will be 10 x 10 m (100m2) and should be permanently marked for future use. PlotLatitude Longitude Plot Camp 57.74603 ‐155.62326 Plot Runway 57.74699 ‐155.62665 Plot Creek 57.74461 ‐155.62459 Plot Wet Meadow 57.7358 ‐155.63087 Plot Saddle 57.74978 ‐155.62044 Plot Cliff 57.75095 ‐155.61476 Table 1. GPS coordinates for suggested phenology plot locations in Puale Bay, AK 2 Plant Phenology Puale Bay 2010 Figure 1. Location of suggested phenology plots in Puale Bay, AK Survey Methods Plants will be monitored each week for phenology. The target species for phenology are presented in Appendix A. Only species within the plots will be monitored. Once a species has been encountered in a plot, it is not necessary to monitor that species in subsequent plots. Individual plants will be monitored according to the National Phenology Network (NPN) protocols, with data sheets available at www.usanpn.org. Minimizing bias toward early flowering individuals can be accomplished by identifying plants before flowering occurs. 3 Plant Phenology Puale Bay 2010 SPECIES COMPOSITION AND ABUNDANCE Site Selection Using GIS (Arcmap 9.3), 50 points were randomly selected within 1 km of camp. The elimination of points in unsuitable areas; the ocean, beach, rock/gravel areas, barren ground, rock/cliff faces, areas with high disturbance, and any points within 100 m of the creek; resulted in 20 remaining plot points (Appendix C). A field crew will visit these points in numerical order to verify suitability. Distance to camp will not be a consideration. After five plots are selected, in accordance with wilderness rules, they should be permanently marked for consistency. These permanent markers will represent the center of the plots. Once the plots have been established, crews can revisit them in whichever order they choose. Survey Methods Species abundance and composition will be studied with a point intercept technique. At each of the plot locations, a circular plot with a 10-m radius will be used. From the center of the plot (designated with rebar or another permanent marker), using measuring tape, extend four 10- m transects in each of the cardinal compass directions. Along each transect at 0.5 m intervals, species composition will be assessed, resulting in 80 points per plot. Construct a 2 m sampling pole out of ¼ in. PVC pipe. Mark the pole at one meter, resulting in two strata. At each sampling point, vertically position the pole on the right 4 Plant Phenology Puale Bay 2010 side of the measuring tape, facing the pole forward for consistency. Starting from the top of the pole and moving downward at each transect point, all species will be recorded, along with the height stratum it touches (one or two meter) (Appendix D). This will give an indication of species presence and abundance. An individual should only be recorded as hitting the pole once, but multiple individuals should be recorded as such. Depending on high or low investment in the project, individuals can be keyed out to species or family levels, respectively. If an unknown specimen is encountered, collect an identical specimen from outside the plot for future identification. If there are no species present at a point, record it as “No species present”. Percent cover can be obtained by counting the number of times a species touches the pole during the four transects and dividing it by the total number of plot points, which is 80 points (Point Intercept (PO)) (Appendix E). Repeat for all plots. Any species encountered within the 10 m radius, but not hit during the point counts should be recorded as additional species present. These plots will be monitored once between 15 and 31 July of each sampling year. BENEFITS/DRAWBACKS By incorporating a multiple plot/transect quantitative method of sampling, over multiple years, inter-annual variation should be adequately documented and allow managers to detect major changes in localized plant community composition and abundance. These methods would also allow for easier plant recognition and more consistent observations of phenology. Having two plot sets (phenology and abundance/composition plots) will also reduce pre- survey trampling by observers. Construction of these plots provides an opportunity for additional monitoring. Vertical structure of vegetation can be monitored more intensively within the point intercept plots by marking the pole in one centimeter increments to measure plant height. Substrate type at each of the plot points could be sampled using a point intercept method. Soil sampling could also be conducted, depending on future objectives. There are several drawbacks to implementing this type of project. It will be more labor intensive and require more time in comparison to the current phenology monitoring system. Currently, the National Phenology Network (NPN) does not have the majority of these species in their database. As a result, phenology data cannot be submitted. Recommendations to include these species have been given to the network, but future follow-up is required. 5 Plant Phenology Puale Bay 2010 During the 2010 field season, monitoring individual plants proved difficult. Frequent rain and wind resulted in low or absent flower and fruit production in several monitored individuals, and flags and individuals were often removed or killed by wildlife. The difficulties associated with monitoring an individual plant could be reduced by monitoring plot populations. This, however, is not part of the NPN protocol and may exclude the dataset from inclusion in the NPN database. If data is not collected for inclusion in the NPN database, the data sheets in Appendix A can be used for monitoring. CONCLUSION Implementing a plot based phenology method would be beneficial. The use of this plot based method will minimize search time for plants in the future and decrease data biasing towards early flowering individuals of each species. Utilization of this method will allow observers to gain familiarity with plants and identify them during vegetative stages. In addition to reporting phenology data, species abundance and composition data would be gained. With the concern over global warming, consistency in plots would allow changes to be noticed and tracked over time. 6 Plant Phenology Puale Bay 2010 LITERATURE CITED Chapin III, F. S., G. R. Shaver, A. E. Giblin, K. J. Nadelhoffer, and J. A. Laundre. 1995. Responses of arctic tundra to experimental and observed changes in climate. Ecology 76: 694- 711. Euskirchen, E.